Yes, your posts are defensive, which is understandable. I think people here are concerned for you, that it will happen again (it will, in my opinion and experience), and they/ we would hope that you come to see this clearly soon to save you from more pain.
That may sound patronising written down. It isn't meant to be. I defended my ex when he shagged around, I spent many an hour convincing myself that his desperate cries of "I'll do anything" and his half hearted attempts at counselling were the clarion call of a new, improved relationship. They weren't. My self esteem continued to be eroded and he continued his revolting entitled behaviour in various different ways.
I thought I was "in charge" of it all, that I understood it all, that I had a handle on it. I thought I could help him, be his friend (pahahaha to me).
I look back now and see that as one part of the whole process of coming to terms with what was done to me.
Don't underestimate the massive physical and emotional shock you're in right now, it will carry on affecting you, and you will adjust to it, deal with it. Just don't bury yourself in it by kidding yourself that you're doing it for the greater good of the family, or the kids.
The day I finally said I'd had enough was when I realised, on a day I'll never ever forget, that being around him making out all was well was actually damaging our children. That was the day his stuff was put in bin bags and the children and I have never looked back.
Take care of yourself, and put on your armour, you're going to need it.